Explained by Jeanine M. Schmidt, Thomas D. Light, and Bruce M. Gamble.
On the choice of deposit models
This tract in east-central Alaska is permissive for Kipushi-type deposits, as described by Cox and Bernstein (1986), because it has the appropriate geologic setting (a continental platform or shelf with continental or passive margin rifting) and host rocks (dolostone, shale and shallow-water or platform carbonate rocks) for the deposit model.
On the delineation of permissive tracts
This tract is defined by Paleozoic platform carbonate rocks. Where the environment of deposition is not known or indeterminate, thick carbonate rocks of possible shelf, slope, or deeper-water-facies are included. Paleozoic metamorphic rocks that contain minor marble units of unknown origin, such as the biotite gneiss and amphibolite (PzpCb of Foster, 1976), have not been included in this tract. In the Eagle and Charley River quadrangles geologically favorable units include the limestones of the Tindir Group, the Funnel Creek Limestone, the Hillard Limestone, and the Calico Bluff Formation. The western portion of this tract includes the Paleozoic limestones of the Quail, Amy Creek, Schwatka, and minor other units.
Important examples of this type of deposit
There are no Kipushi-type deposits known in this tract.
On the numerical estimates made
There are no tonnage and grade curves for Kipushi-type deposits. No quantitative estimates of the number of undiscovered deposits was attempted.
Cox, D.P., and Bernstein, L.R., 1986, Descriptive model of Kipushi Cu-Pb-Zn, in Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 227.
Foster, H.L., 1976, Geologic map of the Eagle quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-922, scale 1:250,000.